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| Brophy, Deirdre; Haynes, Paula; Arrizabalaga, Haritz; Fraile, Igaratza; Fromentin, Jean-marc; Garibaldi, Fulvio; Katavic, Ivan; Tinti, Fausto; Karakulak, F. Saadet; Macias, David; Busawon, Dheeraj; Hanke, Alex; Kimoto, Ai; Sakai, Osamu; Deguara, Simeon; Abid, Nouredinne; Santos, Miguel Neves. |
| Two stocks of bluefin tuna (Thunnus thynnus) inhabit the north Atlantic; the western and eastern stocks spawn in the Gulf of Mexico and the Mediterranean Sea respectively. Trans-Atlantic movements occur outside spawning time whereas natal homing maintains stock structure. Commercial fisheries may exploit a mixed assemblage of both stocks. The incorporation of mixing rates into stock assessment is precluded by uncertainties surrounding stock discrimination. Otolith shape descriptors were used to characterise western and eastern stocks of Atlantic bluefin tuna in the present study and to estimate stock composition in catches of unknown origin. Otolith shape varied with length and between locations and years. Within a restricted size range (200-297-cm fork... |
| Tipo: Text |
Palavras-chave: Elliptical Fourier analysis; Population structure; Stock mixture analysis. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00346/45745/45381.pdf |
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| Moore, Claire; Lynch, Deirdre; Clarke, Maurice; Officer, Rick; Mills, Jane; Dufour, Jean-louis; Brophy, Deirdre. |
| Sprat is a pelagic species of increasing commercial interest in European waters, yet little is known about its biology or the drivers of its population fluctuations. As a result, the species is currently without an analytical assessment or forecast across much of the North East Atlantic. The objectives of this study were to: verify otolithbased age estimation of sprat; assess the precision, bias and reproducibility of these age estimates; and, determine the age structure of sprat within one North East Atlantic management unit (Celtic Seas ecoregion). Samples were collected over three years (2011, 2013 & 2014) from both commercial catches and scientific surveys. Counts of daily increments in otoliths were used to establish when the first annulus was... |
| Tipo: Text |
Palavras-chave: Sprat; Age verification; Otolith; Marginal increment analysis; Age structure. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00485/59692/62883.pdf |
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